Abstract [en]

In two review articles leading European and American researchers have stated that particles in emissions from residential wood combustion and emissions from small-scale biomass burning in general must be regarded as harmful to health during exposure, even in the low concentrations normally found in outdoor air. However, what is missing is knowledge about how this toxicity changes and may be affected when modern combustion technology is used and how different biomass fuels relate in this context.

Because of this, the objective with this work was to determine the influence of combustion conditions in a modified pellet stove on the composition of particulate matter in the emissions with respect to the distribution of organic and elemental carbon. A further purpose was to investigate whether it is possible to generate a stable "sooty" burning state for longer periods of time to be used in future toxicological studies of biomass emission particles.

The results showed that it is possible, by adjusting the parameters that was available, to generate stable conditions of different types of combustion in the currently used and modified pellet stove. Both the total mass concentration of particles and the distribution of organic and elemental carbon in the particulate matter varied. This is promising and shows that it is possible to create, in a controlled manner, incomplete combustion conditions where the particles have different characteristics and properties.

In order to conduct more detailed studies, however, it is recommended that certain improvements and development of technology is implemented, to enable better control and flexibility. This can be done either with a rebuilt pellet stove or a completely new self-designed reactor. This should be applied to verify the results obtained before any comprehensive study on particle properties based on the results achieved in this work is performed.